Capacitor discharge ignition (CDI) systems are widely used with internal combustion engines, especially light duty combustion engines employed by hand-held tools. In addition to a number of other components, a CDI system typically has some type of stop switch that allows an operator to shut the engine down when it is running. Stop switches can include, but are not limited to, on/off switches, momentary switches, and positive off/automatic on type switches.
On/off switches generally involve an operator moving the switch to a desired state before the engine can operate in that state. For instance, if an engine is running and the operator wishes to turn it off, then the operator must move the on/off switch to the ‘off’ position. Before the operator can turn the engine on again, the on/off switch must be moved to the ‘on’ position; thus, turning the engine off and on requires a minimum of two activations of the on/off switch.
Momentary switches, on the other hand, require an operator to hold down the switch while the engine shuts down; if the switch is not engaged for the requisite amount of time, then it is possible for the engine to resume operation when the operator disengages it. Unlike on/off switches, momentary switches do not require the switch to be reset back to some ‘on’ position before the engine can be restarted.
Positive off/automatic on switches allow an operator to shut the engine down simply by pressing the switch for a brief moment, after which the switch automatically resets such that the engine can be restarted without further switch activation. As previously stated, the aforementioned on/off switch types are only examples of some of the different switch types that can be used by CDI systems, as others also exist.